Drinking Bird,USA ASTM certificate happy bird, perpetual motion bird ,children education toys
The Original Drinking birds are toy heat engines which mimics the motions of a bird drinking from a fountain or other water source. It is sometimes considered a perpetual motion device.
When the head of the bird is moistened with water, then it will repeatedly bend down and appear to be drinking from a cup water which it is in front of it. The dunking is due to the evaporating water , which cools the head reducing the pressure of the gas inside. The liquid inside the bird rises up from his tail towards his head, causing the bird to bend down and appear to be drinking. When the bird dunks, the liquid returns to its tail, and the process begins again. In essence this is a small, cleverly designed thermodynamic engine which only needs water to run!
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